Gonzap is a antagonist in the videogames Pokémon Colosseum and Pokémon XD: Gale of Darkness. He's the leader of Team Snagem, a criminal organization operating in Orre for some time. His wanted poster is quite prominently featured in Chief Sherles' office.
Gonzap is a large, mustached man who resembles a turn of the century strongman. He erupts into rage when Wes betrays Team Snagem, blows up their base and steals the Snag Machine.
Gonzap seemed to have some sort of father/son relationship with Wes. The gang leader agreed to help Cipher carry out their plans so that Team Snagem would be provided with powerful technology and Shadow Pokémon. In return, Team Snagem steals Pokémon from innocent trainers, so that they could be turned into Shadow Pokémon.
Gonzap confronted Wes and Rui in one of the top floors of Realgam Tower, but he was defeated and his Shadow Skarmory was snagged.
After Evice was defeated, he attacked Wes and Rui again at the Team Snagem hideout. After Gonzap's second loss to Wes, he vanished - never to be seen again during the events of Pokémon Colosseum.
Pokémon XD: Gale of Darkness
In Pokémon XD: Gale of Darkness, he learns of Michael's Snag Machine, and has it stolen from him by a few members of Team Snagem. After Michael confronts Gonzap at the Snagem Hideout, Gonzap returns the Snag Machine. He emits that the Snag Machine wouldn't even fit on his massive biceps. He later assists Michael at Cipher's Key Lair by having Wakin's Gloom put a few guards to sleep.
During the end of the game, Gonzap is seen along with the "good" characters of the game.